Herein are described a process for repairing used fuser members in an attempt to return them back to near-original condition. After a fuser roller has been installed in an electrophotographic, electrostatographic, xerographic, or like machine, for example a copy or printing machine, the combination of fuser oil or fuser release agent, such as silicone oil and toner, forms a sticky gel that adheres to the fuser roll surface. In turn, this coating reduces the fuser roll performance and life. Ultimately this gel will cause the fuser roll to fail based on print or copy quality. Described herein is a method that will strip away the gel and generate a new, almost original fuser roller. The process entails using a superfinishing process, and a series of finishing papers. In embodiments, specific grit (having specific particle size ranges) of paper is used. Also, in embodiments, a certain number of passes are used. In embodiments, the roll profile is straightened. Specifically, in the event that the roller may have grooves in it from paper edge wear, these grooves will be removed by embodiments of the process described herein.
In a typical electrostatographic printing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of toner. The visible toner image is then in a loose powdered form and can be easily disturbed or destroyed. The toner image is usually fixed or fused upon a support, which may be a photosensitive member itself, or other support sheet such as plain paper.
The use of thermal energy for fixing toner images onto a support member is well known. In order to fuse toner material onto a support surface permanently by heat, it is necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This heating causes the toner to flow to some extent into the fibers or pores of the support member. Thereafter, as the toner material cools, solidification of the toner material causes the toner material to be firmly bonded to the support.
Typically, thermoplastic resin particles are fused to the substrate by heating to a temperature of between about 90° C. to about 160° C. or higher depending upon the softening range of the particular resin used in the toner. It is not desirable, however, to raise the temperature of the substrate substantially higher than about 200° C. because of the tendency of the substrate to discolor at such elevated temperatures particularly when the substrate is paper.
Several approaches to thermal fusing of toner images have been described in the art. These methods include providing the application of heat and pressure substantially concurrently by various means: a roll pair maintained in pressure contact; a belt member in pressure contact with a roll; and the like. Heat may be applied by heating one or both of the rolls, plate members or belt members. The fusing of the toner particles takes place when the proper combination of heat, pressure and contact time are provided. The balancing of these parameters to bring about the fusing of the toner particles is well known in the art, and they can be adjusted to suit particular machines or process conditions.
After repeated fusing cycles, the fusing surface of the fusing member will eventually exhibit unsatisfactory toner release, leading to poor quality prints. More specifically, as set forth above, after a fuser roller has been installed in an electrophotographic, electrostatographic, xerographic, or like machine, for example a copy or printing machine, the combination of fuser oil or fuser release agent, such as silicone oil, and toner forms a sticky gel that adheres to the roll surface. In turn, this coating reduces the roll performance and life. Ultimately this gel will cause the roll to fail based on print or copy quality. Typically, the fuser member is then either tossed away or recycled by stripping off all the coatings and then recoating the substrate to produce a new fuser member.
U.S. Pat. No. 6,289,587 discloses a method for reusing a fuser member comprised of an outer layer having an original fusing surface that is deficient, and the process involves removing a portion of the thickness of the outer layer including the original fusing surface to create on the remaining outer layer a new fusing surface.
Known processes for renewing the surface of a used fuser member include simple polishing of the outside surface of the fuser roller with sandpaper. Although this process may remove some of the gel, the roll produced was not straight and may not have had the same diameter as a new roll. Also, the print quality was compromised. Further, such renewed rollers did not have increased roller life, and failed within an undesirable amount of time.
Thus, there is a need for an improved process for renewing the surface of a used fuser roller, which also allows for a straight roll profile, wherein the roller grooves from paper edge wear are removed. In addition, there is a need for an improved process for renewing the surface of a used fuser roller, wherein the roller produced has an increased life over other fuser rollers processed by known renewal methods. In addition, there is a need for improved print quality.